1. General
This specification contains amino acid sequence information prepared using PatentIn Version 3.1, presented herein after the Abstract. Each sequence is identified in the sequence listing by the numeric indicator <210> followed by the sequence identifier (e.g. <210>1, <210>2, etc). The length of each sequence and source organism are indicated by information provided in the numeric indicator fields <211> and <213>, respectively. Sequences referred to in the specification are defined by the term “SEQ ID NO:”, followed by the sequence identifier (eg. SEQ ID NO: 1 refers to the sequence designated as <400>1).
As used herein the term “derived from” shall be taken to indicate that a specified integer may be obtained from a particular source albeit not necessarily directly from that source.
Throughout this specification, unless the context requires otherwise, the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated step Or element or integer or group of steps or elements or integers but not the exclusion of any other step or element or integer or group of elements or integers.
Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is to be understood that the invention includes all such variations and modifications. The invention also includes all of the steps, features, compositions and compounds referred to or indicated in this specification, individually or collectively, and any and all combinations or any two or more of said steps or features.
The present invention is not to be limited in scope by the specific examples described herein. Functionally-equivalent products, compositions and methods are clearly within the scope of the invention, as described herein.
All the references cited in this application are specifically incorporated by reference herein.
The present invention is performed without undue experimentation using, unless otherwise indicated, conventional techniques of molecular biology, microbiology, virology, recombinant DNA technology, peptide synthesis in solution, solid phase peptide synthesis, and immunology. Such procedures are described, for example, in the following texts that are incorporated by reference:    1. Sambrook, Fritsch & Maniatis, Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratories, New York, Second Edition (1989), whole of Vols I, II, and III;    2. DNA Cloning: A Practical Approach, Vols. I and II (D. N. Glover, ed., 1985), IRL Press, Oxford, whole of text;    3. Oligonucleotide Synthesis: A Practical Approach (M. J. Gait, ed., 1984) IRL Press, Oxford, whole of text, and particularly the papers therein by Gait, pp 1-22; Atkinson et al., pp 35-81; Sproat et al., pp 83-115; and Wu et al., pp 135-151;    4. Nucleic Acid Hybridization: A Practical Approach (B. D. Hames & S. J. Higgins, eds., 1985) IRL Press, Oxford, whole of text;    5. Animal Cell Culture: Practical Approach, Third Edition (John R. W. Masters, ed., 2000), ISBN 0199637970, whole of text;    6. Immobilized Cells and Enzymes: A Practical Approach (1986) IRL Press, Oxford, whole of text;    7. Perbal, B., A Practical Guide to Molecular Cloning (1984);    8. Methods In Enzymology (S. Colowick and N. Kaplan, eds., Academic Press, Inc.), whole of series;    9. J. F. Ramalho Ortigão, “The Chemistry of Peptide Synthesis” In: Knowledge database of Access to Virtual Laboratory website (Interactive, Germany);    10. Sakakibara, D., Teichman, J., Lien, E. Land Fenichel, R. L. (1976). Biochem. Biophys. Res. Commun. 73 336-342    11. Merrifield, R. B. (1963). J. Am. Chem. Soc. 85, 2149-2154.    12. Barany, G. and Merrifield, R. B. (1979) in The Peptides (Gross, E. and Meienhofer, eds.), vol. 2, pp. 1-284, Academic Press, New York.    13. Wünsch, E., ed. (1974) Synthese von Peptiden in Houben-Weyls Methoden der Organischen Chemie (Müler, E., ed.), vol. 15, 4th edn., Parts 1 and 2, Thieme, Stuttgart.    14. Bodanszky, M. (1984) Principles of Peptide Synthesis, Springer-Verlag, Heidelberg.    15. Bodanszky, M. & Bodanszky, A. (1984) The Practice of Peptide Synthesis, Springer-Verlag, Heidelberg.    16. Bodanszky, M. (1985) Int. J. Peptide Protein Res. 25, 449-474.    17. Handbook of Experimental Immunology, Vols. I-IV (D. M. Weir and C. C. Blackwell, eds., 1986, Blackwell Scientific Publications).
2. Description of the Related Art
Immunotherapy or vaccination are attractive for the prophylaxis or therapy of a wide range of disorders, such as, for example, certain infectious diseases, or cancers. However, the application and success of such treatments are limited in part by the poor immunogenicity of the target CTL epitope. Synthetic peptides, representing T cell immunogens elicit only weak immunity when delivered in isolation and as a consequence, are not effective in vaccine compositions. Full-length proteins containing CTL epitopes do not efficiently enter the MHC class I processing pathway. Additionally, CTL epitopes are HLA-restricted and the large degree of HLA polymorphism in human populations means that CTL-based vaccines may not provide broad coverage to all genotypes within a population.
Several techniques are used to enhance the immune response of a subject to a peptide immunogen.
It is known that utilization of an adjuvant formulation that is extrinsic to the peptide immunogen (i.e. it is mixed with the immunogen prior to use), such as, for example, complete Freund's adjuvant (CFA), will enhance the immune response of a subject to a peptide immunogen. However, many of the adjuvants currently available are too toxic for use in humans, or simply ineffective. Moreover, adjuvants of this type require prior formulation with the peptide immunogen—immediately before administration, such formulations often having a low solubility or being insoluble.
Lipopeptides, wherein a lipid moiety that is known to act as an adjuvant is covalently coupled to a peptide immunogen, may be capable of enhancing the immunogenicity of an otherwise weakly immunogenic peptide in the absence of an extrinsic adjuvant [Jung et al., Angew Chem, Int Ed Engl 10, 872, (1985); Martinon et al., J Immunol 149, 3416, (1992); Toyokuni et al., J Am Chem Soc 116, 395, (1994); Deprez, et al., J Med Chem 38, 459, (1995); and Sauzet et al., Vaccine 13, 1339, (1995); BenMohamed et al., Eur. J. Immunol. 27, 1242, (1997); Wiesmuller at al., Vaccine 7, 29, (1989); Nardin et al., Vaccine 16, 590, (1998); Benmohamed, et al. Vaccine 18, 2843, (2000); and Obert, et al., Vaccine 16, 161, (1998)]. Suitable lipopeptides show none of the harmful side effects associated with adjuvant formulations, and both antibody and cellular responses have been observed against lipopeptides.
Several different fatty acids are known for use in lipid moieties. Exemplary fatty acids include, but are not limited to, palmitoyl, myristoyl, stearoyl and decanoyl groups or, more generally, any C2 to C30 saturated, monounsaturated, or polyunsaturated fatty acyl group is thought to be useful.
The lipoamino acid N-palmitoyl-S-[2,3-bis(palmitoyloxy)propyl]cysteine, also known as Pam3Cys or Pam3Cys-OH (Wiesmuller et al., Z. Physiol. Chem. 364 (1983), p 593), is a synthetic version of the N-terminal moiety of Braun's lipoprotein that spans the inner and outer membranes of Gram negative bacteria. Pam3Cys has the structure of Formula (I):

U.S. Pat. No. 5,700,910 to Metzger et al (Dec. 23, 1997) describes several N-acyl-S-(2-hydroxyalkyl)cysteines for use as intermediates in the preparation of lipopeptides that are used as synthetic adjuvants, B lymphocyte stimulants, macrophage stimulants, or synthetic vaccines. Metzger et al. also teach the use of such compounds as intermediates in the synthesis of Pam3Cys-OH (Wiesmuller et al., Z. PhysioL Chem. 364 (1983), p 593), and of lipopeptides that comprise this lipoamino acid or an analog thereof at the N-terminus. The lipopeptides are prepared by coupling a lipoamino acid moiety to the peptide moiety during the synthesis process.
Pam3Cys when coupled to a CTL epitope peptide has been shown to be capable of stimulating virus-specific cytotoxic T lymphocyte (CTL) responses against influenza virus-infected cells (Deres et al., Nature 342, 561, 1989) and to elicit protective antibodies against foot-and-mouth disease (Wiesmuller et al., Vaccine 7, 29, 1989; U.S. Pat. No. 6,024,964 to Jung et al., Feb. 15, 2000) when coupled to the N-terminus of an appropriate synthetic B cell epitope.
Recently, Pam2Cys (also known as dipalmitoyl-5-glyceryl-cysteine or S-[2,3-bis(palmitoyloxy)propyl]cysteine), an analogue of Pam3Cys, has been synthesised (Metzger, J. W., A. G. Beck-Sickinger, M. Loleit, M. Eckert, W. G. Bessler, and G. Jung. 1995. J Pept Sci 1:184.) and been shown to correspond to the lipid moiety of MALP-2, a macrophage-activating lipopeptide isolated from mycoplasma (Sacht, G., A. Marten, U. Deiters, R. Sussmuth, G. Jung, E. Wingender, and P. F. Muhlradt. 1998. Eur J Immunol 28:4207: Muhlradt, P. F., M. Kiess, H. Meyer, R. Sussmuth, and G. Jung. 1998. Infect Immun 66:4804: Muhlradt, P. F., M. Kiess, H. Meyer, R. Sussmuth, and G. Jung. 1997. J Exp Med 185:(1951). Pam2Cys has the structure of Formula (II):

Pam2Cys is reported to be a more potent stimulator of splenocytes and macrophages than Pam3Cys (Metzger et al., J Pept. Sci 1, 184, 1995; Muhlradt et al., J Exp Med 185, 1951, 1997; and Muhlradt et al., Infect Immun 66, 4804, 1998).
Generation of a strong CD8+ T cell response against a given CTL epitope requires the generation of a strong T helper cell response. CD4+ T-helper cells function in cell-mediated immunity (CMI) by secreting sufficient cytokines, such as, for example IL-2, to thereby facilitate the expansion of CD8+ T cells or by interacting with the antigen presenting cell (APC) thereby rendering it more competent to activate CD8+ T cells. Accordingly, it is desirable to administer a CTL epitope in conjunction with at least one T-helper cell epitope (Vitiello et al., J. Clin. Invest. 95, 341-349, 1995; Livingston et al., J. Immunol. 159, 1383-1392, 1997). These epitopes are recognized by T-helper cells in the context of MHC class II molecules on the surface of the APC.
The CTL epitope or isolated epitope can be administered in conjunction with a large protein having a range of T helper epitopes in order to accommodate the diversity of class II alleles within a population of individuals. Alternatively, promiscuous or permissive T-helper epitope-containing peptides are administered in conjunction with the CTL epitope or epitopes. Promiscuous or permissive T-helper epitope-containing peptides are presented in the context of a vast majority of MHC class II haplotypes, such that they induce strong CD4+ T helper responses in the majority of an outbred human population. Examples of promiscuous or permissive T-helper epitopes are tetanus toxoid peptide, Plasmodium falciparum pfg27, lactate dehydrogenase, and HIVgp120 (Contreas et al., Infect. Immun, 66, 3579-3590, 1998; Gaudebout et al., J. A.I.D.S. Human Retrovirol 14, 91-101, 1997; Kaumaya et al., J. Mol. Recog. 6, 81-94, 1993; and Fern and Good J. Immunol. 148, 907-913, 1992). Ghosh et al., Immunol 104, 58-66, 2001 and International Patent Application No. PCT/AU00/00070 (WO 00/46390) also describe promiscuous T-helper epitopes from the fusion protein of Canine Distemper Virus (CDV-F). Certain promiscuous T-helper epitopes promote strong CTL responses to a given CTL epitope, and can bypass certain haplotype restricted immune responses (Kaumaya et al., J. MoL Recog. 6, 81-94, 1993).
Routinely, a vaccine preparation will comprise a mixture of polypeptides comprising the T-helper cell epitope and CTL epitope, however it is also known to consist of a single polypeptide comprising both the T-helper epitope and the CTL epitope.